Reactionless Test to Identify Dynamic Young’s Modulus and Damping of Isotropic Plastic Materials

Abstract

Due to more stringent legal sound regulations and customer demand of quieter products, the acoustic requirements for product design become a major task in the product development. For the requirement for lighter structures, synthetic materials like glass fibers become more prominent in recent designs. For high accurate simulation corresponding material data are needed. But concerning isotropic plastics the Young’s modulus and damping are highly frequency- and temperature-dependent. A novel test to determine the frequency- and temperature-dependent Young’s modulus and damping of isotropic plastics will be shown in this paper. With a special test facility a sample is excited reactionless by a constant repeatable force during measuring the surface velocity. A novel contactless sample suspension is developed. The modal parameters, response frequency and damping, are extracted from these measurements. With the assistance of FEA simulations the Young’s modulus can be adapted step by step to these modal parameters. The Young’s modulus can be extracted frequency- and temperature-dependent.